Operation Control Method

ABSTRACT

An operation control method for controlling operation of a plurality of construction machines that perform excavation while moving is described. Because a moving speed of a second construction machine at a time of excavation and an excavation time of the second construction machine are set based on a moving speed of a first construction machine at a time of excavation and an excavation time of the first construction machine, it is possible to achieve efficient excavation work with good usability.

TECHNICAL FIELD

The present invention relates to an operation control method for controlling an operation of a plurality of construction machines that perform excavation while moving.

BACKGROUND

In construction machines, the work quality may depend on the skill level of an operator, and it is known that, for example, a difference also appears in cycle time of excavation and loading work. Therefore, JP Patent Publication No. JP 2016-156193 A describes providing operation support information to an operator with low skill or switching to automatic driving.

SUMMARY

However, the operation support system described in Patent Publication No. JP 2016-156193 A merely discloses a concept of operation support and is not easy to use in view of an actual site.

Therefore, an object of the present invention is to provide a user-friendly operation control method when a plurality of construction machines are used in a site.

An operation control method according to the present invention is an operation control method for controlling an operation of a plurality of construction machines that perform excavation while moving, and the method includes setting a moving speed of a second construction machine at a time of excavation and an excavation time of the second construction machine based on a moving speed of a first construction machine at a time of excavation and an excavation time of the first construction machine.

According to the present invention, because the moving speed of the second construction machine at the time of excavation and the excavation time of the second construction machine are set based on the moving speed of the first construction machine at the time of excavation and the excavation time of the first construction machine, it is possible to realize efficient excavation work with good usability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a towed scraper of the present embodiment.

FIG. 2 is a diagram illustrating a state in which a plurality of towed scrapers exist in a construction yard.

FIG. 3 is a block diagram of a main part of the present embodiment.

FIG. 4 is a diagram illustrating a flowchart executed by a control device of the present embodiment.

FIG. 5 is a diagram illustrating a flowchart executed by a central control device of the present embodiment.

FIG. 6 is a timing chart of the present embodiment.

FIG. 7 is a timing chart of a comparative example.

DETAILED DESCRIPTION

Hereinafter a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by the embodiment described below.

First Embodiment

FIG. 1 is a schematic view illustrating a towed scraper 100 of the present embodiment. The towed scraper 100 of the present embodiment includes a towing vehicle 1 that is a driving vehicle and a scraper vehicle 20.

The scraper vehicle 20 according to the present embodiment is used as a towed vehicle towed by a large truck or another towing vehicle 1.

FIG. 2 is a diagram illustrating a state in which a plurality of (three in FIG. 2 ) towed scrapers 100 exist in a construction yard. In the present embodiment, the towed scraper 100 moves along a traveling path 30 in the arrow direction, performs excavation at an excavated area 31, and scatters an excavated object obtained by the excavation to a scattered area 32. Note that, in the present embodiment, the term “towed scraper 100” is used in the case of being collectively referred, and in the case of being individually referred to, reference numerals with alphabets are used for description, for example, a towed scraper 100 a, a towed scraper 100 b, and a towed scraper 100 c. The same applies to the towing vehicle 1 and the scraper vehicle 20.

Towing Vehicle

As illustrated in FIG. 1 , the towing vehicle 1 tows the scraper vehicle 20. The towing vehicle 1 of the present embodiment can adopt a dump truck, and for example, can adopt an articulated dump truck. In such an articulated dump truck, because a function and each component as a vehicle are the same as those in a conventional vehicle, the description thereof will be simplified.

FIG. 3 is a block diagram of a main part of the present embodiment, and in the following, the description of the configuration of the towing vehicle 1 continues with reference to FIG. 3 . Note that, in order to simplify the block diagram of FIG. 3 , a towing vehicle 1 a and a towing vehicle 1 b are illustrated in FIG. 3 , both having the same configuration, and therefore the towing vehicle 1 a will be described.

The towing vehicle 1 a includes an operation unit 2 a, a speedometer 3 a, a hydraulic unit 4 a, a communication device 5 a, a memory 6 a, a time-measuring instrument 7 a, and a control device 8 a.

The operation unit 2 a is a generic term for well-known configurations such as a handle, a gear shift lever, a blinker, a wiper, an accelerator, and a brake.

The speedometer 3 a detects the speed of the towing vehicle 1 a, and various sensors such as a vehicle speed sensor that detects the rotation speed of the shaft and a sensor using the output of a global navigation satellite system (GNSS) can be applied to the speedometer 3 a.

The hydraulic unit 4 a transmits fluid with a high pressure generated inside a cylinder (not illustrated) to a power drive through a pipe or the like, and the fluid is supplied to a first hydraulic cylinder 26 a and a second hydraulic cylinder 27 a of a scraper vehicle 20 a in the present embodiment.

The communication device 5 a is a wireless communication unit that accesses a central control device 50 or a wide area network such as the Internet, and transmits a detection result of the speedometer 3 a, a detection result of the time-measuring instrument 7 a, and the like to the central control device 50 in the present embodiment.

The memory 6 a is a nonvolatile memory (for example, a flash memory), and stores the detection result of the speedometer 3 a, the detection result of the time-measuring instrument 7 a, and various data for driving the towing vehicle 1 a. In addition, the memory 6 a stores a program for driving the towing vehicle 1 a and various programs related to, for example, a flowchart of FIG. 4 described later.

The time-measuring instrument 7 a measures a time (e.g., a time required) for each process of excavation, transportation, discharging, and redirection of the scraper vehicle 20 a described later. Note that the time-measuring instrument 7 a may be provided in the scraper vehicle 20 a instead of the towing vehicle 1 a.

The control device 8 a includes a CPU and controls the towing vehicle 1 a and the scraper vehicle 20 a. In the present embodiment, the towing vehicle 1 a is a reference vehicle, and the towing vehicle 1 b and the subsequent vehicles are controlled based on the driving state of the towing vehicle 1 a (details will be described later). Note that the towing vehicle 1 a may be driven by a person (operator), and the towing vehicle 1 b and the subsequent vehicles may be automatically driven, being not driven by a person. In the present embodiment, a skilled person (operator) drives the towing vehicle 1 a.

Scraper Vehicle

Hereinafter the scraper vehicle 20 will be described with reference to FIG. 1 . The scraper vehicle 20 is connected to the towing vehicle 1 by a hitch 21 that is a connection device. The hitch 21 is detachable from the towing vehicle 1, and the scraper vehicle 20 includes a flexible ball joint 22 provided at one end on the towing vehicle 1 side and a flexible ball joint (not illustrated) provided at the other end of the hitch 21 on the scraper vehicle 20 side.

In addition to the hitch 21 and the ball joint 22 described above, the scraper vehicle 20 includes a frame 23, a bowl 24, a scraper 25, a first hydraulic cylinder 26, and a second hydraulic cylinder 27.

The frame 23 is a metal frame that supports a structure such as the bowl 24, and the bowl 24 has an opening on the lower surface side and has an open upper surface, and accommodates an excavated object, such as sediment excavated by the scraper 25, through the opening.

The scraper 25 is a blade-shaped or spatula-shaped member for scraping sediment on a traveling surface such as the ground surface. The scraper 25 is provided integrally with the bowl 24 at the bottom of the bowl 24 in the present embodiment.

Because the bowl 24 and the scraper 25 are integrally provided, the scraper 25 can dig into the ground surface and excavate sediment when the first hydraulic cylinder 26 tilts the bowl 24 toward the ground surface. In addition, the bowl 24 is provided with the opening (not illustrated), and an excavated object excavated by the scraper 25 is accommodated in the bowl 24 from the opening (not illustrated) when the bowl 24 is inclined toward the ground surface.

When the excavation by the scraper 25 is completed, the first hydraulic cylinder 26 tilts the bowl 24 toward the ground, so that the scraper 25 is separated from the ground surface.

The first hydraulic cylinder 26 is connected to the hydraulic unit 4. The first hydraulic cylinder 26 brings the scraper 25 into a state in which the scraper 25 is allowed to dig into the ground surface and excavate sediment and a state in which the scraper 25 is separated from the ground surface as described above.

The second hydraulic cylinder 27 is connected to the hydraulic unit 4 and is provided on the rear end side of the bowl 24. The second hydraulic cylinder 27 is in a shortened state when the scraper vehicle 20 performs excavation, so that an excavated object is accommodated in the bowl 24. By contrast, to discharge the excavated object loaded on the bowl 24, at the scattered area 32, the second hydraulic cylinder 27 extends and discharges the excavated object from the opening of the bowl 24.

When the time-measuring instrument 7 is provided in the scraper vehicle 20, it is preferable to provide a control device including a CPU, a communication device capable of communicating with the towing vehicle 1, the central control device 50, and the like.

The central control device 50 includes a CPU, a communication device, and a time-measuring instrument, and controls the plurality of towed scrapers 100. In the present embodiment, the central control device 50 applies an operation by a person driving the towing vehicle 1 a, as the reference, to the control of the towing vehicle 1 b and the subsequent vehicles. Specifically, the central control device 50 detects the time of each process of excavation, transportation, discharging, and redirection of the towing vehicle 1 a and the moving speed of the towing vehicle 1 a in each process, and applies the detected results to the operation control of the towing vehicle 1 b and the subsequent vehicles.

Description of Flowchart

FIG. 4 is a diagram illustrating a flowchart executed by the control device 8 a of the present embodiment, FIG. 5 is a diagram illustrating a flowchart executed by the central control device 50 of the present embodiment, and FIG. 6 is a timing chart of the present embodiment. Hereinafter the operation of the present embodiment will be described with reference to the flowcharts of FIGS. 4 and 5 and the timing chart of FIG. 6 . Here, the excavation in the timing chart of FIG. 6 is the excavation at the excavated area 31 of FIG. 2 , and the transportation in the timing chart is the transportation of the excavated object from the excavated area 31 to the scattered area 32 (also call a moving process). In addition, the discharging in the timing chart is the discharging of the excavated object at the scattered area 32 (also called a discharging process), and the redirection in the timing chart is the movement from the scattered area 32 to the excavated area 31 (also called a redirection process). Note that the towed scraper 100 a continuously moves from the excavation to the redirection. The towed scraper 100 a does not stop until a series of operations is completed.

Note that the flowchart of FIG. 5 and the timing chart of FIG. 6 are for a case where the seven towed scrapers 100 construct a construction yard.

In the timing chart of FIG. 6 , the length in the lateral direction schematically indicates the length of time. It is assumed that the flowchart of FIG. 4 starts from the time point when the towed scraper 100 a arrives at the excavated area 31.

The control device 8 a determines whether excavation at the excavated area 31 has started (Step S1). The control device 8 a determines that the excavation starts when the hydraulic unit 4 a supplies hydraulic pressure to the first hydraulic cylinder 26 a in accordance with an operation by the operator. The control device 8 a repeats Step S1 until the hydraulic unit 4 a supplies hydraulic pressure to the first hydraulic cylinder 26 a. In the present embodiment, the control device 8 a detects the speed of the towing vehicle 1 a by the speedometer 3 a as the flowchart is started.

When the determination at Step S1 is positive, the control device 8 a starts time measurement of an excavation time by the time-measuring instrument 7 a (Step S2). When the first hydraulic cylinder 26 a causes the scraper 25 a to dig into the ground surface, the sediment excavation is started. Note that the excavation is performed while the towed scraper 100 a moves on the excavated area 31. Here, the control device 8 a may store the operation status of the hydraulic unit 4 a due to an operation by the operator, in the memory 6 a. As a result, the control device 8 a can recognize the amount by which a scraper 25 a digs into the ground surface. The control device 8 a may store the operation status of the hydraulic unit 4 a in the memory 6 a every predetermined time (for example, several seconds), or may store in the memory 6 a when the hydraulic pressure of the first hydraulic cylinder 26 a changes.

The control device 8 a determines whether the excavation has completed (Step S3). The control device 8 a determines that the excavation has completed when the hydraulic unit 4 a stops the supply of hydraulic pressure to the first hydraulic cylinder 26 a in accordance with an operation by the operator. The control device 8 a repeats Step S3 until the hydraulic unit 4 a stops the supply of hydraulic pressure to the first hydraulic cylinder 26 a. Note that it is preferable to stop the supply of hydraulic pressure to the first hydraulic cylinder 26 a and maintain the height (in Z-axis direction) of the towed scraper 100 a even during excavation in accordance with the digging amount of the towed scraper 100 a. Note that the control device 8 a may determine that the excavation has completed, when the control to shorten the first hydraulic cylinder 26 a is performed, instead of determining that the excavation has completed, when the hydraulic unit 4 a stops the supply of hydraulic pressure to the first hydraulic cylinder 26 a by in accordance with an operation by the operator.

When the determination at Step S3 is positive, the control device 8 a completes the time measurement of the excavation time by the time-measuring instrument 7 a and transmits data of the excavation time to the central control device 50 by the communication device 5 a (Step S4). In addition, the control device 8 a transmits data of the speed (for example, average speed) of the towing vehicle 1 a detected by the speedometer 3 a from the start of excavation to the completion of excavation to the central control device 50.

The control device 8 a determines whether the towed scraper 100 a has started conveyance (Step S5). As described above, because the towed scraper 100 a does not stop until the series of operations is completed, the control device 8 a determines that the towed scraper 100 a has started the conveyance when the hydraulic unit 4 a stops the supply of the hydraulic pressure to the first hydraulic cylinder 26 a. The control device 8 a proceeds to Step S6.

When the determination at Step S5 is positive, the control device 8 a starts time measurement of a conveyance time by the time-measuring instrument 7 a (Step S6). In the present embodiment, the control device 8 a detects the speed of the towing vehicle 1 a that is conveying by the speedometer 3 a as the conveyance is started.

The control device 8 a determines whether the conveyance has completed (Step S7). The control device 8 a determines that the conveyance has completed when the hydraulic unit 4 a supplies hydraulic pressure to the second hydraulic cylinder 27 a in accordance with an operation by the operator. Alternatively, when the GNSS detects arrival at the scattered area 32 the control device 8 a may determine that the conveyance has completed.

When the determination at Step S7 is positive, the control device 8 a completes the time measurement of the transportation time by the time-measuring instrument 7 a and transmits data of the transportation time to the central control device 50 by the communication device 5 a (Step S8). In addition, the control device 8 a transmits data of the speed (for example, average speed) of the towing vehicle 1 a detected by the speedometer 3 a from the start of transportation to the completion of transportation to the central control device 50.

The control device 8 a determines whether the discharging by the second hydraulic cylinder 27 a has started (Step S9). The control device 8 a determines that the carrying-out has started when the hydraulic unit 4 a supplies hydraulic pressure to the second hydraulic cylinder 27 a in accordance with an operation by the operator. The control device 8 a repeats Step S9 until the hydraulic unit 4 a supplies hydraulic pressure to the second hydraulic cylinder 27 a.

When the determination at Step S9 is positive, the control device 8 a starts time measurement of a discharging time by the time-measuring instrument 7 a (Step S10). In the present embodiment, the control device 8 a detects the speed of the towing vehicle 1 a that is discharging by the speedometer 3 a as the discharging is started.

The control device 8 a determines whether the discharging has completed (Step S11). The control device 8 a determines that the discharging has completed, when the hydraulic unit 4 a stops the supply of the hydraulic pressure to the second hydraulic cylinder 27 a. Alternatively, when the GNSS detects departure from the scattered area 32, the control device 8 a may determine that the discharging has completed. Note that the control device 8 a may determine that the excavation completes, when the control to shorten the first hydraulic cylinder 26 a is performed, instead of determining that the excavation has completed, when the hydraulic unit 4 a stops the supply of hydraulic pressure to the first hydraulic cylinder 26 a by in accordance with an operation by the operator.

When the determination at Step S11 is positive, the control device 8 a completes time measurement of the discharging time by the time-measuring instrument 7 a and transmits data of the discharging time to the central control device 50 by the communication device 5 a (Step S12). In addition, the control device 8 a transmits data of the speed (for example, average speed) of the towing vehicle 1 a detected by the speedometer 3 a from the start of discharging to the completion of discharging to the central control device 50.

The control device 8 a determines whether the redirection has started (Step S13). The control device 8 a determines that the redirection starts when the hydraulic unit 4 a stops the supply of hydraulic pressure to the second hydraulic cylinder 27 a in accordance with an operation by the operator. The control device 8 a repeats Step S13 until the hydraulic unit 4 a stops the supply of hydraulic pressure to the second hydraulic cylinder 27 a.

When the determination at Step S13 is positive, the control device 8 a starts time measurement of a redirection time by the time-measuring instrument 7 a (Step S14). In the present embodiment, the control device 8 a detects the speed of the towing vehicle 1 a that is being redirected, by the speedometer 3 a as the redirection is started.

The control device 8 a determines whether the redirection has completed (Step S15). The control device 8 a determines that the redirection has completed, when the hydraulic unit 4 a supplies the hydraulic pressure to the first hydraulic cylinder 26 a. Alternatively, when the GNSS detects arrival at the excavated area 31, the control device 8 a may determine that the redirection has completed.

When the determination at Step S15 is positive, the control device 8 a completes the time measurement of the redirection time by the time-measuring instrument 7 a and transmits data of the redirection time to the central control device 50 by the communication device 5 a (Step S16). In addition, the control device 8 a transmits data of the speed (for example, average speed) of the towing vehicle 1 a detected by the speedometer 3 a from the start of redirection to the completion of redirection to the central control device 50 and completes this flowchart. Note that the second and subsequent series of processes may be performed without completing this flowchart. Whether to perform the second and subsequent processes may be determined by an operator or may be determined by the central control device 50.

Furthermore, in this flowchart, the control device 8 a may transmit the operation status of the hydraulic unit 4 a stored in the memory 6 a, that is, the amount by which the scraper 25 a digs into the ground surface, to the central control device 50 via the communication device 5 a.

Next, the flowchart executed by the central control device 50 will be described with reference to FIG. 5 . In the present embodiment, the flowchart of FIG. 5 is started when the data of the excavation time and the data of the speed of the towing vehicle 1 a are received at Step S4 in the flowchart of FIG. 4 . In the present embodiment, it is assumed that the towed scraper 100 b is on standby at the excavated area 31.

The central control device 50 sets N to 1 as an N value representing the unit number (the towed scraper 100 a is referred to as the unit 1, the towed scraper 100 b is referred to as the unit 2, . . . , a towed scraper 100 g is referred to as the unit 7) of the towed scraper 100 (Step S101).

The central control device 50 determines whether the unit 1 (the towed scraper 100 a) has completed excavation (Step S102). As described above, the central control device 50 has received the data of the excavation time and the data of the speed of the towing vehicle 1 a, and therefore proceeds to Step S103.

The central control device 50 adds 1 to the N value, representing the unit number of the towed scraper 100, so that the N value is 2 (Step S103). As a result, the control target device of the central control device 50 is switched to the towed scraper 100 b as the unit 2.

The central control device 50 instructs the towed scraper 100 b as the unit 2 to perform excavation (Step S104) and starts the time measurement of the excavation time (Step S105).

Specifically, at Step S104, the central control device 50 transmits an excavation instruction and a moving speed to a control device 8 b via a communication device 5 b of the towing vehicle 1 b. In addition, the central control device 50 may transmit the operation status of the hydraulic unit 4 a to the control device 8 b and transmit the amount by which a scraper 25 b digs into the ground surface to the control device 8 b.

As illustrated in FIG. 6 , the control device 8 b causes a hydraulic unit 4 b to supply hydraulic pressure to a first hydraulic cylinder 26 b almost simultaneously with the completion of excavation by the towed scraper 100 a, and the control device 8 b starts excavation by the scraper 25 b. In this case, the control device 8 b can make the amount by which the scraper 25 b digs into the ground surface the same as the amount by which the scraper 25 a digs into the ground surface by making the amount of pressurized hydraulic fluid to be supplied to the first hydraulic cylinder 26 b the same as the amount of pressurized hydraulic fluid supplied by the first hydraulic cylinder 26 a.

In addition, the control device 8 b drives the towing vehicle 1 b based on the received moving speed. The control device 8 b performs speed control based on the speed detected by a speedometer 3 b and the average speed of the towing vehicle 1 a at the time of excavation such that the average speed of the towing vehicle 1 b at the time of excavation is the same as the average speed of the towing vehicle 1 a at the time of excavation.

Note that the time measurement at Step S105 is performed on the central control device 50 in the present embodiment, but the time measurement may be performed by a time-measuring instrument 7 b of the towing vehicle 1 b.

The central control device 50 determines whether predetermined time has elapsed since excavation was started (Step S106). In the present embodiment, the predetermined time is a time during which the scraper 25 a of the scraper vehicle 20 a performed excavation. When the time measurement at Step S105 is to be performed on the time-measuring instrument 7 b of the towing vehicle 1 b, the predetermined time may be transmitted to the control device 8 b via the communication device 5 b, and the control device 8 b may determine whether the predetermined time has elapsed.

The central control device 50 repeats Step S106 until the predetermined time elapses. The central control device 50 proceeds to Step S107 when the predetermined time elapses.

The central control device 50 instructs the unit 2 to complete excavation and gives instructions for the transportation and subsequent processes (Step S107).

The central control device 50 determines whether the N value, representing the unit number of the towed scraper 100, is 7 (Step S108). Here, because the N value is 2, the central control device 50 returns to Step S102, confirms that excavation by the unit 2 has been completed, and at subsequent Step S103, adds 1 to the N value, representing the unit number of the towed scraper 100, so that the N value is 3 (Step S103). The central control device 50 performs Step S104 and subsequent steps, and the central control device 50 repeats this flowchart until the N value reaches 7.

As illustrated in FIG. 6 , the seven towed scrapers 100 can construct the construction yard by referring the excavation time, the transportation time, the discharging time, and the redirection time of the towed scraper 100 a as the unit 1, as the references.

FIG. 7 is a timing chart of a comparative example, and the excavation time is different for each unit. In the comparative example of FIG. 7 , because the construction is performed by the six towed scrapers 100, the productivity is lower than that in a case where the construction is performed by the seven towed scrapers 100.

In addition, in the comparative example of FIG. 7 , when the towed scraper 100 a as the unit 1 starts the second excavation, a towed scraper 100 f as the unit 6 is performing the excavation at the excavated area 31. Therefore, it is possible that the towed scraper 100 a as the unit 1 and the towed scraper 100 f as the unit 6 approach each other and lead to an unexpected accident. In order to avoid the approach of the towed scraper 100 a as the unit 1 and the towed scraper 100 f as the unit 6, the towed scraper 100 a as the unit 1 has to stand by, but causes a loss of time.

By contrast, in the timing chart of FIG. 6 , when the excavation by the towed scraper 100 g as the unit 7 is completed, the redirection of the towed scraper 100 a as the unit 1 is completed and the towed scraper 100 a as the unit 1 starts the second excavation. Therefore, safe construction without loss of time can be performed. With the operation control method by the central control device 50 of the present embodiment, it is possible to realize efficient excavation work.

In the above description, the excavation time, the transportation time, the discharging time, and the redirection time of the towed scraper 100 a as the unit 1 are matched with those of the towed scrapers 100 b to 100 g as the other units, but the present invention is not limited thereto.

For example, the excavation time of the towed scraper 100 a as the unit 1 may be matched with the excavation time of the towed scrapers 100 b to 100 g as the other units, and the total time of the transportation time, the discharging time, and the redirection time of the towed scraper 100 a as the unit 1 may be matched with the total time of the transportation time, the discharging time, and the redirection time of the towed scrapers 100 b to 100 g as the other units.

In addition, in order to let the time T from the start of excavation to the completion of redirection of the unit 1 coincides with the sum of the excavation times t of the units 1 to N, T=N×t is acceptable.

The towed scraper 100 a as the unit 1 may be replaced with another towed scraper 100 when the towed scraper 100 a is being redirected after the first excavation, transportation, and discharging are completed. In this case, the other towed scraper 100 may be operated in an unmanned manner. Alternatively, the towed scraper 100 a as the unit 1 may be replaced with another towed scraper 100 when the towed scraper 100 a is being redirected after the n-th (n is a natural number greater than or equal to 2) excavation, transportation, and discharging are completed.

In addition, on the first day, the towed scraper 100 a as the unit 1 may perform data collection for excavation, transportation, discharging, and redirection; and on the second and subsequent days, the plurality of towed scrapers 100 may be operated in an unmanned manner based on the data acquired on the first day. In this case, the central control device 50 may correct the data acquired on the first day on the basis of environmental conditions such as weather and wind speed.

For example, when the wind is stronger on the second day than on the first day or the ground surface is wet by slight rain, the central control device 50 may perform control to decelerate the average moving speed of the towed scraper 100 by about 5 to 10%. The central control device 50 may also extend the moving time of the towed scraper 100 by about 5 to 10%.

The embodiment described above is merely an example for describing the present invention, and various modifications can be made without departing from the gist of the present invention. For example, the central control device 50 may control the plurality of towed scrapers 100 in a construction yard B different from a construction yard A based on data acquired in the construction yard A. In this case, the central control device 50 may start construction in the construction yard B at a time point when the first excavation, transportation, discharging, and redirection in the construction yard A are completed.

The following is a list of reference signs used in the drawing figures and in this specification.

-   -   1 Towing vehicle     -   3 Speedometer     -   4 Hydraulic unit     -   5 Communication device     -   7 Time-measuring instrument     -   8 Control device     -   20 Scraper vehicle     -   25 Scraper     -   26 First hydraulic cylinder     -   27 Second hydraulic cylinder     -   50 Central control device     -   100 Towed scraper 

1. An operation control method for controlling an operation of a plurality of construction machines that perform excavation while moving, the method comprising setting a moving speed of a second construction machine at a time of excavation and an excavation time of the second construction machine based on a moving speed of a first construction machine at a time of excavation and an excavation time of the first construction machine.
 2. The operation control method according to claim 1, wherein the first construction machine includes a first scraper that performs the excavation, the second construction machine includes a second scraper that performs the excavation, and an amount by which the first scraper digs into a ground surface and an amount by which the second scraper digs into the ground surface are controlled to be the same.
 3. The operation control method according to claim 1, comprising a moving process of moving from an excavated area where the excavation is performed to a scattered area where an excavated object obtained by the excavation is scattered, wherein a moving time of the first construction machine and a moving time of the second construction machine in the moving process are set to be the same.
 4. The operation control method according to claim 3, wherein a moving speed of the first construction machine and a moving speed of the second construction machine in the moving process are set to be the same.
 5. The operation control method according to claim 1, comprising: a moving process of moving from an excavated area where the excavation is performed to a scattered area where an excavated object obtained by the excavation is scattered; a discharging process of discharging the excavated object at the scattered area; and a redirection process of redirection from the scattered area to the excavated area, wherein the second construction machine is controlled such that time required for each of the moving process, the discharging process, and the redirection process of the first construction machine is equal to time required for each of the moving process, the discharging process, and the redirection process of the second construction machine.
 6. The operation control method according to claim 5, wherein the moving speed of the second construction machine is controlled such that the moving speed of the first construction machine in each of the moving process, the discharging process, and the redirection process is equal to the moving speed of the second construction machine in each of the moving process, the discharging process, and the redirection process.
 7. The operation control method according to claim 1, wherein operation of the second construction machine is controlled in an unmanned manner.
 8. The operation control method according to claim 1, comprising: obtaining data concerning a drive of the first construction machine; and applying the data to excavation on the following day and thereafter.
 9. The operation control method according to claim 8, comprising: correcting the data in accordance with environmental condition.
 10. The operation control method according to claim 9, wherein the environmental condition includes weather.
 11. The operation control method according to claim 1, comprising: obtaining data concerning a drive of the first construction machine at a first yard, wherein the data is applied at a second yard that is different from the first yard.
 12. The operation control method according to claim 1, wherein the excavation of the first construction machine starts in accordance with end of excavation of the last construction machine. 